COVID-19 has multiple facesJanuary 20, 2021
ImmunoSensation scientists present latest findings on the coronavirus in "Genome Medicine"
According to current studies, the COVID-19 disease which is caused by the SARS-CoV-2 coronavirus comprises at least five different variants. These differ in how the immune system responds to the infection. Researchers from the German Center for Neurodegenerative Diseases (DZNE) and the University of Bonn, together with other experts from Germany, Greece and the Netherlands, present these findings in the scientific journal "Genome Medicine".
Their results may help to improve the treatment of the disease. Infection with SARS-CoV-2 can manifest in different ways: Many of those affected do not even seem to notice the presence of the virus in their bodies. In other cases, the effects can include flu-like symptoms and neurological disorders to severe and even life-threatening pneumonia. "The classification of COVID-19 into mild and severe courses falls short. The disease is much more diverse, and for each affected person, one certainly would want a therapy that is tailored to fit. What helps one person may be ineffective for another," said Dr. Anna Aschenbrenner, a scientist of the LIMES Institute at the University of Bonn and the DZNE's Systems Medicine division. "In this respect, it is obvious to want to understand what underlies these differences. If we can pin them down to scientific criteria and categorize patients accordingly, this increases the chances of effective treatment. We therefore took a look at the immune system. Because many studies are indicating that its response to infection with SARS-CoV-2 plays a crucial role in the course of COVID-19," said Aschenbrenner, who is a member of the "ImmunoSensation2" Cluster of Excellence at the University of Bonn.
"First of all, it is important to note that the expression patterns of immune cells in people with COVID-19 differ fundamentally from those in healthy individuals. The gene activity we can detect in the blood is strongly altered. But there are also striking differences among patients. On this basis, we have identified five different groups. We refer to them as molecular phenotypes," said Dr. Thomas Ulas, an expert in bioinformatics at the DZNE. "Two of them represent severe disease courses. The others have more moderate symptoms." The classification was based solely on transcriptome data. Only in retrospect, molecular phenotypes were matched to registered clinical courses.
COVID-19 Is Different
The researchers used their findings to compare COVID-19 with other diseases and also with data from healthy individuals. For this purpose, they were able to draw on data from the "Rhineland Study" - a population study conducted by the DZNE in the Bonn area - as well as on data from scientific databases. For the comparison, a large spectrum of diseases was considered: including viral infections such as influenza, infections with HIV and Zika, bacterial infections such as tuberculosis and bacterial sepsis, and inflammatory diseases such as rheumatoid arthritis. "All five COVID-19 phenotypes are different from the other diseases we studied," Ulas said, summing up the findings. "Apparently, COVID-19 has a unique biology that is reflected in the gene activity of immune cells in the blood. Insofar, expression analysis could be used to diagnose COVID-19. This would be an alternative or complement to current methods."
Publication: Disease severity-specific neutrophil signatures in blood transcriptomes stratify COVID-19 patients, Aschenbrenner et al., Genome Medicine (2021), DOI: 10.1186/s13073-020-00823-5;
Link to the study: https://genomemedicine.biomedcentral.com/articles/10.1186/s13073-020-00823-5
Dr. Anna Aschenbrenner
LIMES Institute at the University of Bonn; Systems Medicine division at DZNE
Phone: +49 228 4330 2690